#!/bin/bash -eu
# Copyright 2016 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
################################################################################

# Fuzzer runner. Appends .options arguments and seed corpus to users args.
# Usage: $0 <fuzzer_name> <fuzzer_args>

export PATH=$OUT:$PATH
cd $OUT

DEBUGGER=${DEBUGGER:-}

FUZZER=$1
shift

# This env var is set by CIFuzz. CIFuzz fills this directory with the corpus
# from ClusterFuzz.
CORPUS_DIR=${CORPUS_DIR:-}
if [ -z "$CORPUS_DIR" ]
then
  CORPUS_DIR="/tmp/${FUZZER}_corpus"
  rm -rf $CORPUS_DIR && mkdir -p $CORPUS_DIR
fi

SANITIZER=${SANITIZER:-}
if [ -z $SANITIZER ]; then
  # If $SANITIZER is not specified (e.g. calling from `reproduce` command), it
  # is not important and can be set to any value.
  SANITIZER="default"
fi

if [[ "$RUN_FUZZER_MODE" = interactive ]]; then
  FUZZER_OUT="$OUT/${FUZZER}_${FUZZING_ENGINE}_${SANITIZER}_out"
else
  FUZZER_OUT="/tmp/${FUZZER}_${FUZZING_ENGINE}_${SANITIZER}_out"
fi

function get_dictionary() {
  local options_file="$FUZZER.options"
  local dict_file="$FUZZER.dict"
  local dict=""
  if [[ -f "$options_file" ]]; then
    dict=$(sed -n 's/^\s*dict\s*=\s*\(.*\)/\1/p' "$options_file" | tail -1)
  fi
  if [[ -z "$dict" && -f "$dict_file" ]]; then
    dict="$dict_file"
  fi
  [[ -z "$dict" ]] && return
  if [[ "$FUZZING_ENGINE" = "libfuzzer" ]]; then
     printf -- "-dict=%s" "$dict"
  elif [[ "$FUZZING_ENGINE" = "afl" ]]; then
     printf -- "-x %s" "$dict"
  elif [[ "$FUZZING_ENGINE" = "honggfuzz" ]]; then
     printf -- "--dict %s" "$dict"
  else
     printf "Unexpected FUZZING_ENGINE: $FUZZING_ENGINE, ignoring\n" >&2
  fi
}

rm -rf $FUZZER_OUT && mkdir -p $FUZZER_OUT

SEED_CORPUS="${FUZZER}_seed_corpus.zip"

if [ -f $SEED_CORPUS ] && [ -z ${SKIP_SEED_CORPUS:-} ]; then
  echo "Using seed corpus: $SEED_CORPUS"
  unzip -o -d ${CORPUS_DIR}/ $SEED_CORPUS > /dev/null
fi

OPTIONS_FILE="${FUZZER}.options"
CUSTOM_LIBFUZZER_OPTIONS=""

if [ -f $OPTIONS_FILE ]; then
  custom_asan_options=$(parse_options.py $OPTIONS_FILE asan)
  if [ ! -z $custom_asan_options ]; then
    export ASAN_OPTIONS="$ASAN_OPTIONS:$custom_asan_options"
  fi

  custom_msan_options=$(parse_options.py $OPTIONS_FILE msan)
  if [ ! -z $custom_msan_options ]; then
    export MSAN_OPTIONS="$MSAN_OPTIONS:$custom_msan_options"
  fi

  custom_ubsan_options=$(parse_options.py $OPTIONS_FILE ubsan)
  if [ ! -z $custom_ubsan_options ]; then
    export UBSAN_OPTIONS="$UBSAN_OPTIONS:$custom_ubsan_options"
  fi

  CUSTOM_LIBFUZZER_OPTIONS=$(parse_options.py $OPTIONS_FILE libfuzzer)
fi

if [[ "$FUZZING_ENGINE" = afl ]]; then

  # Set afl++ environment options.
  export ASAN_OPTIONS="$ASAN_OPTIONS:abort_on_error=1:symbolize=0:detect_odr_violation=0:"
  export MSAN_OPTIONS="$MSAN_OPTIONS:exit_code=86:symbolize=0"
  export UBSAN_OPTIONS="$UBSAN_OPTIONS:symbolize=0"
  export AFL_I_DONT_CARE_ABOUT_MISSING_CRASHES=1
  export AFL_SKIP_CPUFREQ=1
  export AFL_TRY_AFFINITY=1
  export AFL_FAST_CAL=1
  export AFL_CMPLOG_ONLY_NEW=1
  export AFL_FORKSRV_INIT_TMOUT=30000
  export AFL_IGNORE_PROBLEMS=1
  export AFL_IGNORE_UNKNOWN_ENVS=1

  # If $OUT/afl_cmplog.txt is present this means the target was compiled for
  # CMPLOG. So we have to add the proper parameters to afl-fuzz.
  test -e "$OUT/afl_cmplog.txt" && AFL_FUZZER_ARGS="$AFL_FUZZER_ARGS -c $OUT/$FUZZER"

  # If $OUT/afl++.dict we load it as a dictionary for afl-fuzz.
  test -e "$OUT/afl++.dict" && AFL_FUZZER_ARGS="$AFL_FUZZER_ARGS -x $OUT/afl++.dict"

  # Ensure timeout is a bit larger than 1sec as some of the OSS-Fuzz fuzzers
  # are slower than this.
  AFL_FUZZER_ARGS="$AFL_FUZZER_ARGS -t 5000+"

  # AFL expects at least 1 file in the input dir.
  echo input > ${CORPUS_DIR}/input

  CMD_LINE="$OUT/afl-fuzz $AFL_FUZZER_ARGS -i $CORPUS_DIR -o $FUZZER_OUT $(get_dictionary) $* -- $OUT/$FUZZER"

  echo afl++ setup:
  env|grep AFL_
  cat "$OUT/afl_options.txt"

elif [[ "$FUZZING_ENGINE" = honggfuzz ]]; then

  # Honggfuzz expects at least 1 file in the input dir.
  echo input > $CORPUS_DIR/input
  # --exit_upon_crash: exit whith a first crash seen
  # -R (report): save report file to this location
  # -W (working dir): where the crashes go
  # -v (verbose): don't use VTE UI, just stderr
  # -z: use software-instrumentation of clang (trace-pc-guard....)
  # -P: use persistent mode of fuzzing (i.e. LLVMFuzzerTestOneInput)
  # -f: location of the initial (and destination) file corpus
  # -n: number of fuzzing threads (and processes)
  CMD_LINE="$OUT/honggfuzz -n 1 --exit_upon_crash -R /tmp/${FUZZER}_honggfuzz.report -W $FUZZER_OUT -v -z -P -f \"$CORPUS_DIR\" $(get_dictionary) $* -- \"$OUT/$FUZZER\""

else

  CMD_LINE="$OUT/$FUZZER $FUZZER_ARGS $*"

  if [ -z ${SKIP_SEED_CORPUS:-} ]; then
    CMD_LINE="$CMD_LINE $CORPUS_DIR"
  fi

  if [ ! -z $CUSTOM_LIBFUZZER_OPTIONS ]; then
    CMD_LINE="$CMD_LINE $CUSTOM_LIBFUZZER_OPTIONS"
  fi

  if [[ ! "$CMD_LINE" =~ "-dict=" ]]; then
    if [ -f "$FUZZER.dict" ]; then
      CMD_LINE="$CMD_LINE -dict=$FUZZER.dict"
    fi
  fi

  CMD_LINE="$CMD_LINE < /dev/null"

fi

echo $CMD_LINE

# Unset OUT so the fuzz target can't rely on it.
unset OUT

if [ ! -z "$DEBUGGER" ]; then
  CMD_LINE="$DEBUGGER $CMD_LINE"
fi

bash -c "$CMD_LINE"

